The field of the present invention is an internal combustion engine having dual operational mode rocker arm assemblies.
Most reciprocating piston internal combustion engines have rocker arms to transmit motion from a rotating cam shaft to a stem of a combustion chamber intake or exhaust poppet valve to open and close the same. Almost universally, the valve is spring-biased shut and the cam, via the rocker arm controls the opening and closing of the valve. One type of rocker arm is the finger follower rocker arm.
In recent times, rocker arm assemblies have been made to selectively deactivate. In one such rocker arm assembly, the rocker arm has an outer body that engages the valve stem and an inner, lost motion arm pivotally mounted on and within the outer body for movement relative to the outer body. The lost motion arm is spring-biased upward against an overhead engine cam center lobe to be pivoted by the same. A latch mechanism with an extendable plunger is positioned within the outer body. The plunger is normally in a position to limit movement of the lost motion arm relative to the outer body so that the cam lobe can pivot the outer body and lost motion arm together as an integral unit to activate the valve stem. Withdrawal of the latch mechanism plunger allows the lost motion arm to freewheel in a lost motion manner without causing partial or full movement of the outer body and valve stem.
To selectively activate the plunger of the rocker arm assembly there is provided a pivotal lever. Typically, reciprocating piston automotive vehicles will have at least one exhaust valve. Most newer engines have one or more intake valves. Accordingly, for each given cylinder, a solenoid will control one or more rocker arm assemblies.
The solenoid actuator must be accurately positioned with respect to the latch mechanism to insure proper plunger operation. Typically, the solenoid actuator was connected with a bracket which in turn was connected with the engine head. Any misalignment between the bracket and the engine head could contribute to a misalignment of the solenoid actuator to the latch mechanism plunger. Therefore, a method to accurately position the solenoid actuator with respect to the plunger which is not susceptible to misalignment of the bracket with respect to the engine head is highly desired.
It is also desired that the solenoid actuator be as small as possible. Typically, the actuator voltage supply wiring harness is exposed to the interior of the engine head, which is a very hostile environment due to the exposure to hot engine oil. Assembly of the wiring harness also consumes a relatively large amount of time.
It is also desirable to provide an apparatus and method of utilization thereof of placement of the solenoids associated with dual operational mode rocker arms which allows placement of all the solenoid actuators in a single manufacturing step.
The present invention provides an internal combustion engine with a cylinder head that includes intake and exhaust passageways which are fluidly connected with respective combustion chambers. A poppet valve is provided for controlling fluid communication between the combustion chamber and the intake or exhaust passageway.
A cover is provided for enclosing the rocker arm assemblies. The cover, often referred to as a cam cover, has a surface for mating with the cylinder head. A gasket is provided which is captured between the mating surface of the cam cover and the cylinder head. The gasket has a generally soft polymeric material which is similar or identical to that currently being utilized for sealing the cam cover to the engine head.
Encapsulated within the generally soft polymeric material is a generally rigid (metallic) bracket frame. The bracket frame provides a highly accurate mounting platform for the solenoids that activates the various rocker arm assemblies of the engine bank. To power the various solenoids, a wiring harness is encapsulated within the gasket.
It is an advantage of the present invention to provide a cam cover gasket which allows highly accurate dimensional placement of the solenoid actuators associated with dual mode operational rocker arm assemblies.
It is a further advantage of the present invention to provide an engine as noted above wherein the wiring harness associated with the solenoids utilized for the dual mode rocker arm assemblies is installed upon installation of the gasket.
Other features and advantages of various embodiments of the present invention will become more apparent to those skilled in the art from a reading of the following detailed description and upon reference to the drawings.